Use macos-13 x86_64 agent for x86_64 build

.github/workflows/release-nightly.yaml

@@ -90,7 +90,7 @@ jobs:
           draft: true
 
   build-darwin-x86_64:
-    runs-on: macos-latest
+    runs-on: macos-13
     name: Build macOS x86_64 binary
     steps:
       - name: checkout code
@@ -100,6 +100,10 @@ jobs:
           repository: anoma/juvix
           ref: main
 
+      - name: install stack
+        run: |
+          brew install haskell-stack
+
       - name: Set homebrew LLVM CC and LIBTOOL vars (macOS)
         run: |
           echo "CC=$(brew --prefix llvm@15)/bin/clang" >> $GITHUB_ENV